+
+ <varlistentry><term>update</term>
+ <listitem>
+ <para>
+
+ Update the local keyring with the archive keyring and remove from
+ the local keyring the archive keys which are no longer valid.
+ The archive keyring is shipped in the <literal>archive-keyring</literal> package of your
+ distribution, e.g. the <literal>debian-archive-keyring</literal> package in Debian.
+
+ </para>
+
+ </listitem>
+ </varlistentry>
+
+ <varlistentry><term>net-update</term>
+ <listitem>
+ <para>
+
+ Work similar to the <command>update</command> command above, but get the
+ archive keyring from an URI instead and validate it against a master key.
+
+ This requires an installed &wget; and an APT build configured to have
+ a server to fetch from and a master keyring to validate.
+
+ APT in Debian does not support this command and relies on
+ <command>update</command> instead, but Ubuntu's APT does.
+
+ </para>
+
+ </listitem>
+ </varlistentry>
+ </variablelist>
+</refsect1>
+
+ <refsect1><title>Options</title>
+<para>Note that options need to be defined before the commands described in the previous section.</para>
+ <variablelist>
+ <varlistentry><term>--keyring <replaceable>filename</replaceable></term>
+ <listitem><para>With this option it is possible to specify a specific keyring
+ file the command should operate on. The default is that a command is executed
+ on the <filename>trusted.gpg</filename> file as well as on all parts in the
+ <filename>trusted.gpg.d</filename> directory, through <filename>trusted.gpg</filename>
+ is the primary keyring which means that e.g. new keys are added to this one.
+ </para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1><title>Files</title>
+ <variablelist>
+
+ &file-trustedgpg;
+
+ <varlistentry><term><filename>/etc/apt/trustdb.gpg</filename></term>
+ <listitem><para>Local trust database of archive keys.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term><filename>/usr/share/keyrings/debian-archive-keyring.gpg</filename></term>
+ <listitem><para>Keyring of Debian archive trusted keys.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term><filename>/usr/share/keyrings/debian-archive-removed-keys.gpg</filename></term>
+ <listitem><para>Keyring of Debian archive removed trusted keys.</para></listitem>
+ </varlistentry>
+